Magnetic circuits



Aug. 25,1942. 7 F, VANDER WOUDE 2,294,322

MAGNETIC CIRCUITS Filed April 6, 1940 mmzm m INVENTOR.

Fe/rz E. V4 0:: W000:

ATTORNEYS Patented Aug. 25, 1942 MAGNETIC CIRCUITS Fritz R. van der Woud The General Industries e, Elyria, Ohio, asslgnor to Company, Elyria,

Ohio, a corporation of Ohio Application April 6,1940, Serial No. 328,346

2 Claims.

This invention relates to magnetic circuits, and more particularly to an improved construction for magnet cores and the like.

An object of this invention is to provide an improved sectional construction for magnet cores and the like which will contribute to the economical manufacture and assembly of various electrical devices of which cores form a part.

Another'object of my invention is to provide an improved core construction in which the core can be formed of separate sections so as to facilitate assembly of the energizing coil or other parts of the device embodying such core and in which the core sections are adapted to be readily assembled to form an eflicient and satisfactory core and one in which the core sections are not likely to become loose or accidentally separated.

A further object of my invention is to provide an improved core constructionin which core sections are constructed and arranged to form a joint having low magnetic reluctance and in which spring means is arranged to span the joint and acts on the core sections to prevent opening or separation of the Joint.

My invention may be further briefly summarized as consisting in certain novel combinations and arrangements of parts hereinafter described and particularly set out in the appended claims.

In the accompanying sheet of drawing:

Fig. 1 is a plan view showing a magnet core constructed according to my invention and embodied in an electrical device;

Fig. 2 is an edge view thereof;

Fig. 3 is a plan view showing another magnet core constructed according to my invention; and Figs. 4 and 5 are partial plan views showing still other magnet cores constructed according to my invention. I

For a more detailed description of my invention, further reference will now be made to the.

drawing, but before proceeding with the detailed description. I wish it to be understood that the invention is not to be regarded as limited to the particular core constructions and arrangements herein disclosed-since it may be embodied in various other specific forms of magnet cores and in numerous kinds and types of electromagnetic devices.

In Figs. 1 and 2 I show a magnetic circuit constructed according to my invention and comprising a core I0 having an energizing coil or winding ll thereon. The core in this instance comprises two sections or parts I2 and I3 which, as will be be readily assembled and connected with each other to form a closed magnetic circuit with the coil I i in the desired location thereon.

The core sections i2 and 13 may be of various sizes and shapes depending upon the construction desired and the intended use of the completed core or magnetic circuit formed thereby. Although I show the core H] as composed of only two core sections, it will be understood, of course, that it is within the contemplation of my invention to form a magnetic circuit or core of any desired number of parts or sections.

Core sections intended to be assembled or connected in accordance with my invention, such as the core sections l2 and I3, may be formed as solid bodies of magnetic material, but preferably are of a laminated construction, as shown in Fig. 2, and as is usual in electromagnetic devices in general. The laminations for the core sections l2 and I3 may be stamped from sheet steel, or otherwise constructed, and are arranged in stacks in registering relation with each other and may be retained in such relation by suitable rivets H or other connecting means extending there through.

. The core section I2 may have a U-like portion formed by a pair of arms I 5 and I6 spaced laterally to' receive the coil ll therebetween, and the core section l3 may be in the form of a straight bar or arm of a length to extend through the coil and to connect the outer ends of the arms l5 and i6 of the core section l2.

The meeting portions of the core sections l2 and I3 may be of any shape or formation which will enable these portions to fit together sufficiently tightly to provide a joint having very low magnetic reluctance. In other words, the

' meeting portions of these core sections are prefpresently explained, are so formed that they can 5 erably so formed that they engage or abut each other with metal-to-metal contact and with minimum air space therebetween. Such meeting portions may be in the form of plane faces or can .be of irregular shape for mating or interfitting engagement. As indicated in Fig. 1 the meeting portions of the core sections l2 and I3 may be so formed or disposed as to engage each other to form the joint l1 with the adjacent portions of the core sections extending in angular relation to each other, or in other words, with the meeting core portions forming a corner l8 on the core with the joint .l'l extending across the corner I such as in the diagonal relation illustrated.

For connecting the core sections i2 and I3 with each other in the desired relative arrangement, I employ spring means which draws or serves to hol'dthe meeting portions of the core sections together in the above-mentioned relatively tight metal-to-metal contact. This spring means may comprise one or more curved springs id of the plate or leaf type which are provided with appropriate means or are so shaped as to have gripping engagement with the core portions to be connected. For convenience of manufacture and assembly, theconnection between one of the springs 99 and the core sections may be formed by providing the adjacent or meetin core portions with grooves or recesses 2d and providing the spring with hook-like portions 2! adjacent its ends and adapted to engage in these grooves or recesses. The grooves 2@ may be formed in the outer edges of the. cre sections it and i3 adjacent the ends of the cooperating arm portions thereof and may be cut or otherwise formed in the core sections so as to extend transversely to the planes of the laminations.

When the spring i9 is to be applied to a joint located at a corner of the core, as in the case illustrated in Fig. l, the spring may be arranged to span or extend around the corner with the corner extending into the concavity or recess of the sprim. x

in constructing and assembling the partsconstituting the core it, the core sections i2 and it would first be constructed as separate parts as above described, and after placing the coil it on the core section it, the sections would be brought together into the relative positions shown in Fig. 1 with the ends or meeting portions of the sections engaging each other to form the tight fitting joint Eh The-springs W are then applied to the cooperating portions of the core sections by engaging the hook-like portions 2i oi the springs in. the grooves Or recessesfid. This can be readily done by moving the springs edgewise, that is, at right-angles to the planes of the laminations and thereby sliding or advancing the hook-like portions ii of the springs along the grooves 2d. The spacing of the grooves 2d and the portions oi the springs it are preferably such that when the springs are applied to the adjacent portions of the core sections in this manner, the springs will be stressed or deflected somewhat so thatthey will thereafter act to draw or tightly press the meeting portions of the core sections against each other. While the springs is may be made of any desired width, I prefer to construct them so as to have a width substantially equal to the thickness of the core sections, as shown in Fig. 2 of the drawing.

2 My improved core construction is applicable to magnet circuits in general and can be embodied in numerous different kinds of electrical devices. By way of example, Figs. 1 and 2 show my im-. proved core construction embodied in a small electric motor of the shaded pole type. The moto:- here illustrated has a rotor 22 disposed in an opening 23 of the core section i2 and mounted for rotation therein by means of suitable bearings 2d and 25 in which its shaft 26 is journaled. The bearings 2d and 25 may be carried respectively by bars or plates 2'! and 28 which are arreinred to extend transversely of the frame opening 28 and may be connected with the frame by screws 29 having spacers 89 thereon. Shading coils 3i may be arranged on the core section i2 adjacent the rotor opening 23 thereof. One or more holes bio may be provided in the core is for connecting the motor with a support or base. i

aacasaa be used at certain corners only while a; solid or integral construction 'is provided at the other corners.

My invention is not limited to the use of a connecting spring means at a corner or corners of a magnetic core, but can be used as Well for connecting core portions which extend in alignment with each other. Fig. i'shows one such construction in which core sections 35 and 36 are curved and extend in arcuate alignment with each other and have their adjacent ends connected and held in tight metal-to-metal contact by the spring 3'8 which may be arranged on the outside of the curve so as to span the joint 38. Fig. 5 shows another such arrangement in which core sections 39 and id extend in straight or lineal alignment with each other and are connected by the spring iii arranged to span the joint 62.

Although the core sections illustrated in Figs. 3, 4 and 5 may be of a solid construction, they are preferably also formed as stacks of laminations disposed in registration with each other and connected by rivets 43 extending therethrough.

From the foregoing description and the accompanying drawing, it will now be readily seen that I have provided an improved construction for magnetic circuits, cores and the like which permits such members to be formed of separate parts so as to facilitate the assembly of the electric devices in which they are embodied and yet makes it possible to quickly and easily connect the core sections in a manner such that the joint between the meeting portions of the core sections has m etal-to-metal contact and provides a magnetic path of low reluctance. It will be seen furthermore that in this improved core construction I employ spring means which can be easily applied to the adjacent portions of the core sec- 'tions so as to span the joint formed thereby and which will serve to permanently draw or hold the core sections in the desired metal-tometal engagement with each other.

While I have illustrated and described my improved magnetic circuit or core construction in a more or less detailed manner; it will be understood, of course, that I do not wish to be limited to the particular constructions and arrangements herein disclosed, but regard my invention as including such changes and modifications as do not constitute a departure from the spirit of the invention and the scope of the appended claims. 7

Having thus described my invention, I claim:

I 1. A core for an electromagnetic device comprising two serially related relatively angularly v disposed core elements, each of said elements comprising a stack of elongated fiat laminations, the laminations of each stack having similarly formed end edges disposed in complementary transverse alignment, means maintaining the laminations of each core element in'fixed relatively superposed stacked arrangement, "the aligned lamination edges of one core element abuttingly engaging said' aligned lamination edges of the other element, to cause ,said eiements to substantially define a V, said elements providing the arms thereof, the laminations of each stack each being transversely notched at an edge portion spaced from but near the said end edge thereof with the notches of all said laminations disposed in transverse alignment to provide each of said elements with a transverse groove, said grooves being disposed in parallel spaced relationship at the outer surfaces of, and on the two sides of the apex of said V formation of core elements, and a leaf spring substantially of such U-form as to adapt it to be resiliently expanded to more shallow U-i'orm to snap the ends of the spring into, said parallel grooves, said notches and said spring ends being relatively so formed that the retractive spring effect of the expanded spring will prevent said ends from being accldentally dislodged from said grooves, and will resiliently maintain the abutting lamination edges of the members in pressure abutting contact so as to provide a magnetic Joint of low permeability'.

2. A corefor an electromagnetic device comprising two elongated laminated core elements having complementary end face surfaces extend-- ing transversely thereof in surface abutting engagement with the core elements extending angularly divergingly from the said abutted surfaces, said surfaces comprising edges of the laminations of said elements, the laminations of each element being transversely notched in alignment to provide a groove, the grooves thereby provided for the respective elements being disposed in substantial relative parallel alignment and disposed in outer relativelydiverging faces of the respective elements and in each case near but separated from said abutting surfaces, and a spring provided with a pair of claws, adapted to be resiliently distorted to separate the claws for projection thereof of one said 'claw in each groove, the retractive effect of said spring resiliently exerting force tending to draw said claws toward each other, and said claws and a wall of each said groove being complementarily so formed ;with respect to the direction said force is exerted as to retain said claws in their respective grooves, whereby said spring maintains said end surfaces in good abutting magnetic Joint making pressure contact.

FRITZ R.'VAN na WOUDE. 

